1. Field of the Invention
The present invention relates to boron nitride nanotube paste compositions, electron emission sources including the same, electron emission devices including the electron emission sources, and backlight units and electron emission display devices including the electron emission devices.
2. Description of the Related Art
Generally, electron emission devices are classified into two types: 1) a hot cathode type in which a hot cathode is used as the electron emission source, and 2) a cold cathode type in which a cold cathode is used as the electron emission source. Examples of cold cathode electron emission devices include Field Emitter Array (FEA) devices, Surface Conduction Emitter (SCE) devices, Metal Insulator Metal (MIM) devices and Metal Insulator Semiconductor (MIS) devices, and Ballistic electron Surface Emitting (BSE) devices.
Among these electron emission devices, carbon-type materials are widely used as a constituent of the electron emission source. For example, carbon nanotubes are widely used, which are superior in conductivity, electro-focusing effects, and field emission properties, and have low work functions.
However, since carbon nanotubes reach very high temperatures when emitting electrons, combustion can occur in CO or CO2 even when there is a very small amount of oxygen, thereby burning the ends of the carbon nanotubes. Moreover, properties, such as band gap, change depending on the rolled direction of the carbon nanotube, and since the rolling direction cannot be controlled, it is not possible to control the properties of the conductor or semiconductor. Hence, carbon nanotubes do not have good uniformity or lifespan.